Abstracts

Rationale: Approximately 30% of patients with epilepsy have inadequate control of seizures with drug therapy. We present a cohort of patients with newly-diagnosed epilepsy and assess response to first, second and third adequate trials of antiepileptic drugs (AEDs), as well as the role of EEG and MRI in the development of intractability. Methods: All patients seen in the new-onset seizure clinic at the London Health Sciences Center/University of Western Ontario-Epilepsy Programme, with newly-diagnosed epilepsy, were included in a prospective and systematic way since 2006. Demographics as well as clinical history were obtained. Epilepsy was classified as idiopathic, symptomatic, or cryptogenic. Response to treatment with antiepileptic medication was assessed. Patients were considered to be seizure-free if they had not had seizures of any type in between visits. Results of MRI and EGG were analyzed as well. Results: 174 patients were included. The mean age was 37 years (range: 10-84). Information was available for 139 patients. Of these 83 (59.7%) became seizure free and 56 continued to have seizures. When the two groups were compared, there were no differences in sex, history of febrile seizures, and family history of seizures (p> 0.05). The median age of onset was 36.8 years in those who became seizure free, and 31.2 years for those who persisted in having seizures. Of the ones who did not become seizure free with the first AED trial, response to a second trial of AED was seen in 20 (14.3% of total). Only 1 (0.8%) person became seizure free after a third trial of AED. Mean follow up was 17.2 m (SD /- 10.13m). The most common used AEDs were phenytoin (43), carbamazepine (38), and lamotrigine (29). As a second trial, lamotrigine was the most common used (24). Of those who became seizure free after the first trial of AED, 15 had normal EEG, and 28 normal MRI of the brain. Of the ones who did not become seizure free after 3 trials of AEDs, the EEG was normal in only 5 patients, and the MRI was normal in only 13. Conclusions: Patients who began having seizures early in life and those with symptomatic epilepsy are likely not to become seizure free after treatment with the first AED. In general, response to first AED trial was seen in close to 60% of patients. EEG and MRI findings did not influence prognosis.